It's very easy to filter things out nowadays, George.  All the main email client programs have excellent facilties for noticing a collocation of keywords and dumping those emails.  Or just storing them out of sight, if you don't want to lose them altogether.  I think it's a more effective approach to take control that way, than to fragment an already small intellectual community into single-topic ghettos.  

​You use ​Apple Mail (2.2102); I've never used a Mac, but perhaps these pages may help.

Actually, I think this is the way our reading will go increasingly in the future.  We'll be using aggregators like Feedly that filter things according to our criteria, and provide us with the reading matter we're actually interested in, suppressing everything else.

Best,

Dominik